Investigation of the indium-boron interaction in silicon

The interaction between indium and boron coimplanted in silicon has been investigated. In particular, the effects of the coimplantation on the diffusion and the electrical activation have been studied in comparison with the single B or In implanted samples. It is shown that, by means of coimplantation, it is possible to obtain p-type carrier concentration profiles with a concentration peak higher than the ones achievable by the single In doping, but with the further advantage of a shallower carrier distribution with respect to the single B implant. It is found that this is due to the formation of In-B complexes with an acceptor level deeper than the one related to substitutional B.